Intact rabbit corneas will be cultured in the presence of various isotopically labeled precursors. The cell layers will be removed and the stroma extracted for the fractionation of proteoglycans. The rate of isotope incorporation into the chemically definable proteoglycans will be measured, and relative rates of synthesis of carbohydrate and protein components will be calculated. Any evidence of precursor/product relationships among the proteoglycan species will be sought. By use of pulse-chase labeling experiments the turnover of various proteoglycan species can be evaluated as an initial approach to understanding how the cornea maintains its integrity and function.